Sara, who is curvy, with wavy brown hair and warm eyes, was 32. She was six months into a protracted, painful divorce from her high school sweetheart. She put on a bright smile and gazed at her client’s reflection. He needed his eyebrows done, for sure, she thought.

“Do you want your eyebrows cleaned up, or do you want something special?” she asked.

Her client pulled out a cell phone and showed Sara a photograph of a statuesque woman with a dramatic fall of blond hair, carefully made up.

“I love photography!” Sara said, and they spent the rest of the session talking about photography.

In Hollywood parlance, they met cute. Sara assumed Radinsky was gay, and spent the evening after work telling her friends about “the cool drag queen photographer” she met.

Radinsky went home from the session and posted a picture on Facebook. He loved his reshaped eyebrows and was pleased Sara accepted the Koko alter-identity beginning to dominate his life, though not yet to the point of coming out.

They became friends, and then BFFs. Sara called her new friend Koko, not Ned, and took up the offer to have her portrait taken in Koko’s studio, a short walk from Berenices. On the way to the studio, Koko told Sara, “I’m so glad you’re doing this! I want you to meet my girlfriend.”

“What, your girlfriend?” Sara said. “Like, a real girl?”

“Yeah,” Koko said. “I date women. My gender identification is that of a woman, but I’m attracted to women.”

Something inside Sara shifted.

“Wow,” she said.

Some relationships are uncomplicated. This one is not. The story of the relationship between Sara and Koko has more in common with a Shakespeare mistaken-identity comedy than an article in a bridal magazine.

In strictly biological terms, their wedding next month will be a one-man, one-woman union. (Koko has not undergone sex-reassignment surgery and does not plan to have it done.)

But Koko and Sara each will wear a bridal gown, perfect make-up and carefully coiffed hair.

“Despite the fact that Sara and I both present as women, consider ourselves lesbians and are both wearing wedding gowns, we can get married because the laws all come down to genitalia,” Koko said. “If I went to Trinidad and had genital reassignment surgery, then I could legally become a woman. But then we couldn’t get married. We could only have a civil union.”

Koko is transgender — born male, with the sensibility of a female. The alter-identity of Koko began surfacing in childhood, when frocks were a preference during dress-up play, and there was a recurring dream of being kidnapped and disguised as a girl.

For more than four decades, Ned Radinsky kept the alter-ego Koko Brentano firmly closeted. As Radinsky, he had an impressive career as a photographer, starting with cars and trucks, and later segueing into concerts and musicians. There was a short-lived marriage that ended in divorce.

By 2001, the pressure to live as Koko was increasing. Radinsky moved to a Congress Park house that also served as a new studio named Koko B. Koko was allowed out for trips to gay bars and First Fridays at Tracks, and with trusted friends. But it was still mostly Ned Radinsky who took photographs and who worked part-time at the testosterone-drenched Cigars On Sixth.

” Transgender people transitioning in their 40s, 50s and 60s have often had successful lives playing the role of the gender they were born with,” Koko explained.

“But at some point, something happens. Think of two lines intersecting in a graph. The first line is how much you care about what people think — and when you’re young, you really care about what other people think of you, but as you get older, you don’t care that much.

“The second line represents the stress of suppressing yourself from your real identity. When those two lines cross, that need goes through the roof. And that’s when people come out.”

On Jan. 4, 2010, those lines were close to intersecting.

Sara didn’t know that. She assumed Koko was the confident blond bombshell she first saw in that cellphone photo.

During her chaotic, seemingly endless divorce negotiations, Sara felt pummeled and uncertain. She tried to be upbeat and brave around her daughter and son, then both in elementary school. She wished she had the self-assurance that Koko seemed to possess.

Early in their relationship, Sara mentioned in a phone call that she’d talked about Koko to a client. Koko went cold.

“So, are they cool with it?” Koko asked nervously.

“What’s the big deal?” Sara said.

It was a signal moment for Koko: “I thought, if Sara’s not worried about telling her clients, who pay to see her, that she’s not bothered about me as Koko, then why does it bother me? It was a big realization.”

And it galvanized the event that Koko regards as a coming-out party. Some colleagues at Cigars on Sixth knew about the Koko alter-identity and had suggested hosting an evening, as Koko, at the store. Sara, of course, was all for it.

“Cigars on Sixth is a man-cave,” Koko said. “It’s where boys go to be boys, and hang around other boys. So it was a bit terrifying. I was so sure, in my mind, how different people would react, and who’d be cool with Koko, and who wouldn’t. Well, it was a real eye-opener about how wrong I was. There were people posing for photographs with me that I thought would never be OK with Koko, and others I thought would be cool … weren’t.”

“I had a few inklings, but Ned had not said anything to me about Koko, and that night, it was just done in a fashion that made you go, ‘Wow!’ ” Fitzgerald said.

“He’s my friend. He’s my strong friend as Ned, and my strong friend as Koko. There’s all different layers to this that I can’t get my head around. But can you explain anyone you know? Do you ever really know somebody? The only currency we have is kindness, and Ned has tons of it.”

The transition from friendship to romance began a bit before the Cigars On Sixth event. Sara, tentatively, was starting to date and naturally, called Koko with post-mortem reports.

One evening, friends canceled plans with Sara, and a potential date fizzled out. Feeling rejected and alone, Sara called Koko and asked if she could come over after work.

“It was the stars aligning,” Sara said. “I stayed there that night, and we really haven’t been apart since.”

Unsurprisingly, there have been challenges. Sara’s parents distanced themselves from her. Sara’s longtime friends worried about her. At restaurants, sometimes waiters who arrive at their table are, as Sara puts it, “befuddled until Koko engages them in conversation, and then they just melt.

“This is who I’m with. You can’t argue with how someone identifies with their gender. If you’re the person who identifies with that person, does that make me bisexual, or fluid? One thing I’ve found is that labeling makes things so much more difficult.”

Sara changed her surname to Brentano, the name Koko adopted from the celebrated bookstore in New York City. After a year or so of dating, they disclosed their relationship to Sara’s daughter and son. Today, Sara and Koko share parenting duties with Sara’s ex-husband. The children seem to take the relationship in stride, and both will be members of the wedding party.

Koko lives full-time as a woman now. Sara persuaded Koko to give up the wigs she once favored in exchange for a bleached pixie cut that Sara constantly tousles with her fingers.

The combination of close-cropped platinum hair and Koko’s unaltered, wide-shouldered, broad-chested body in a fitted dress creates a sensational impression when they go out. At Tracks’ First Friday party earlier this month, Koko led Sara through the pulsing crowds of dancers like a nuclear icebreaker ship in high heels.

Sara, a co-owner of Berenices, still specializes in eyebrows and makeup there. She has a loyal following of high-profile clients familiar with the story of her recent life.

“I promised myself that I’d never make excuses again, and if I have a client who has a problem with my relationship with Koko, then I don’t need that client,” she says.

Often, Sara shows up to work in a dress her colleagues haven’t seen before.

“Cute!” they’ll say. “Is it yours, or Koko’s?”

Yes, they wear the same size. Except in shoes, one of the banes of Koko’s life.

“It’s hard to find cute shoes over size 10, and over size 12 is almost impossible, and I wear a women’s size 14 — and I have a wide foot, too,” Koko says.

“Oh, Koko, you have more cute shoes than I do,” Sara says affectionately. “One of the appeals of being with Koko — with me being a girly girl — is having someone to be girly with. I think my past has opened my eyes to love that goes beyond gender. It allows me to love, and accept love, from Koko, but also to love so openly in general. I appreciate genuine unconditional love in a way I may not have quite understood before.”